Touch screens have gained increasing popularity in computer systems and particularly in mobile computing devices, such as laptops, PDAs, media players, game controllers, touchpads, smartphones, etc. As more and more computing devices have become capable of accepting user input by detecting users' tactile pressure and by identifying users' voice commands for instance, hard keyboards have been commonly replaced with virtual input tables, e.g. on-screen soft keyboards. Thus, a touch screen can usually occupy a large portion of an exterior surface of a mobile device.
As consumer demand for device portability has continuously driven size reduction in mobile device designs, touch screen sizes have correspondingly shrunk, making the available display area on such devices increasingly limited. In addition, there are still a few other user Input/Output (I/O) devices, such as a home button, a speaker, a microphone, and a camera lens, that are conventionally arranged on the same exterior surface with the touch screen and compete with the touch screen for area. The functions of these user I/O devices are well known in the art. FIG. 1a is an exterior front view of a typical mobile computing device 100 in accordance with the prior art. Besides the touch screen 102, a loudspeaker 104 and a home button 103 are also disposed on the front side of the device 100. Among the I/O devices, a home button typically takes up a largest area second to the display panel, as illustrated in FIG. 1a. FIG. 1b is an exterior side view of the mobile computing device 100 in accordance with the prior art. It shows the display panel 102, the home button 103, and the loudspeaker 104 are situated on the same side of the device 100.
Due to the limited touch screen size and the even smaller effective viewing area on the touch screen, information is forced to be displayed in small sizes in order to present a reasonable amount of information in one page, which tends to cause eye strain and inconvenience on users.